67 turn signal problem

[Dennis W.]

I have a problem with my 67 coupe left side front turn signal. The right side front and rear signals work fine as does the left rear turn signal. The front right side signal will light up when I turn on my running or head lights however the turn signal does not flash, with or without the lights. Also, the indicator light for the right turn signal on dash blinks as it should but the left indicator does not light up at all. I have looked in the archives and not seen ayone else with this problem or at least none that had the light work but not the turn signal. Any suggestions as to where to start and what to look for would be appreciated. Thanks, Dennis

[Stephen L.]

Re: 67 turn signal problem

Turn on the emergency flashers to see if the light works. If this works it eliminates a wiring problem. You then probably have a faulty turn signal switch.

[Timothy B.]

Re: 67 turn signal problem

Dennis,

Make sure the bulbs are good then get a test light and ground it to a good ground and see if there is power at the bulb socket when you turn the blinkers on. It's a process of elimination but you need to start with the simple things first, don't rule out two separate problems.

[Peter L.]

Re: 67 turn signal problem

Dennis - Don't forget to check & see if both of the brake lights are functioning. Pete

[Gerard F.]

Re: 67 turn signal problem

Turn on the emergency flashers to see if the light works. If this works it eliminates a wiring problem. You then probably have a faulty turn signal switch.

Dennis,

I agree with Steve, the best test of the bulbs and front/rear wiring harnesses is to turn on the hazard flasher. This disconnects the signal circuit and directly wires the element of the signal flasher bulbs. If the left front and dash indicator flash with the hazard on, the bulbs and wiring are OK.

But since you have both a front signal and indicator out on a left turn, I would suspect the signal switch and the little cam on it, which holds it to a left or right turn.

[Donald O.]

Re: 67 turn signal problem

Brake lights work,
turn signals work, front and rear,
parking and tail lamps work.

My hazard flashers used to work, I last checked the operation about 25 years ago, but now they are a no-go. The switch operates as it should. Would this indicate the flasher itself or the TS switch? I replaced it with a GM unit about 27 years ago.

[Timothy B.]

Re: 67 turn signal problem

Donald,

Try another flasher or get a test light and see if there is power at the wires going on either side of the flasher when you put the flashers on. If you have power on one side I suspect the flasher is not working properly as it heats up and opens which causes the flasher operation.

[Dennis W.]

Re: 67 turn signal problem

I tried the hazard flashers and they work rear flashers and right side front but no left side. As before, the left front running light works but no turn signal or flasher. I assume this means no power is getting to the circuit for the flasher and turn signal, any idea which wire I should be tracing for this circuit? thanks, dennis

[Stephen L.]

Re: 67 turn signal problem

Did you replace the bulb...with a "known good bulb". That means that the bulb worked in a different location. If you did that then you are now at the stage of troubleshooting. Obtain a wiring diagram and work back from the light toward the switch looking for voltage, with a meter or probe lite, at the various connections. Don't forget that the emergency flasher should be "on" to supply voltage. There is a connection behind the light in the fender well. The next connection would be at the firewall plug harness. The final connection is under the dash on he steering column, and the final location would be the switch itself. Once you see a voltage then the problem will be in the following section away from the switch. If you don't understand how to read the wiring diagram then you better find someone to help.

[Stephen L.]

Re: 67 turn signal problem

See last sentence.

[Stephen L.]

Re: 67 turn signal problem

I messed up the last reply. The turn signal light is a separate filament from the running light in the same bulb. They work independent of each other, therefore the running light can work while the turn signal will not.

[Gerard F.]

Re: 67 turn signal problem

I tried the hazard flashers and they work rear flashers and right side front but no left side. As before, the left front running light works but no turn signal or flasher. I assume this means no power is getting to the circuit for the flasher and turn signal, any idea which wire I should be tracing for this circuit? thanks, dennis

Dennis,

Here's a wiring diagram of the 67 signal switch:



Sounds like you have a problem in the switch or wiring to the left front or a burned out element in the left front bulb. Does the left indicator on the dash flash with the hazard. If not, that could also be a bulb problem, or a switch/wiring problem.

The wire you should be tracing is the light blue wire (LBL) at the harness connector under the dash coming down from the steering column. (the one next to the black horn wire (HR) in the diagram) You can isolate the problem to the signal switch or the wiring harness, by putting a probe light or voltmeter lead into the connector for the LBL wire and grounding the other lead. No need to disconnect the connector, a probe lead fits nicely into the back of the connector. If the probe light lights or you get 12 V with the hazard flasher or left signal on, then the signal switch is OK, and the problem is further up front.

Note that there are three separate feed circuits to the signal switch: the brakes, signal circuit and the hazard circuit. The running or parking lights circuit has nothing to do with the signal switch and does not run up the column. This circuit feeds a separate element in the same signal bulb.

[Gerard F.]

Re: 67 turn signal problem

Brake lights work,
turn signals work, front and rear,
parking and tail lamps work.

My hazard flashers used to work, I last checked the operation about 25 years ago, but now they are a no-go. The switch operates as it should. Would this indicate the flasher itself or the TS switch? I replaced it with a GM unit about 27 years ago.

Don,

Try what Tim says, see if you have power at the hazard flasher on the fuse box. The hazard flasher feeds the hazard circuit in the signal switch.

If you have power through the flasher and the hazard still don't work, then it could be the hazard switch on the signal switch. See the diagram in the post above.

[Lawrence S.]

Re: 67 turn signal problem

I had the exact same problem, and ultimately had to replace the entire turn signal housing. Worked fine after that.

[Dennis W.]

Re: 67 turn signal problem

Thanks to everyone for your information. I will start to work on the problem today, and have a better idea of what I need to do thanks to everyone. Dennis